xx 2.5.4

//! Hash utilities
//!
//! This module provides hashing functions for files and data.
//!
//! ## Features
//!
//! - `hash` (default): SHA256 and SHA512 support
//! - `hash_md5`: MD5 support (legacy, not recommended for security)
//! - `hash_sha1`: SHA1 support (legacy, not recommended for security)
//! - `hash_blake3`: Blake3 support (fast, modern)
//!
//! ## Examples
//!
//! ```rust,no_run
//! use xx::hash;
//! use std::path::Path;
//!
//! // Hash a file
//! let hash = hash::file_hash_sha256(Path::new("Cargo.toml")).unwrap();
//! println!("SHA256: {}", hash);
//!
//! // Hash bytes
//! let hash = hash::sha256(b"hello world");
//! println!("SHA256: {}", hash);
//! ```

use std::collections::HashMap;
use std::collections::hash_map::DefaultHasher;
use std::hash::{Hash, Hasher};
use std::io::Read;
use std::path::Path;

use sha2::Digest;

use crate::file::display_path;
use crate::{XXError, XXResult, bail, file};

fn hex(bytes: &[u8]) -> String {
    let mut s = String::with_capacity(bytes.len() * 2);
    for b in bytes {
        std::fmt::Write::write_fmt(&mut s, format_args!("{b:02x}")).unwrap();
    }
    s
}

/// Calculate the hash of a value
/// # Arguments
/// * `t` - A value to hash
/// # Returns
/// A hash as a string
/// # Example
/// ```
/// use xx::hash::hash_to_str;
/// let hash = hash_to_str(&"foo"); // 3e8b8c44c3ca73b7
/// ```
pub fn hash_to_str<T: Hash>(t: &T) -> String {
    let mut s = DefaultHasher::new();
    t.hash(&mut s);
    let bytes = s.finish();
    format!("{bytes:x}")
}

/// Calculate the SHA256 checksum of a file
/// # Arguments
/// * `path` - A path to a file
/// # Returns
/// A SHA256 checksum
/// # Errors
/// Returns an error if the file cannot be read
/// # Example
/// ```
/// use std::path::Path;
/// use xx::hash::file_hash_sha256;
/// let hash = file_hash_sha256(Path::new("test/data/foo.txt")).unwrap();
/// ```
pub fn file_hash_sha256(path: impl AsRef<Path>) -> XXResult<String> {
    let path = path.as_ref();
    debug!("Calculating SHA256 checksum for {}", display_path(path));
    let h = file_hash::<sha2::Sha256>(path)?;
    Ok(hex(h.as_slice()))
}

/// Calculate the SHA512 checksum of a file
/// # Arguments
/// * `path` - A path to a file
/// # Returns
/// A SHA512 checksum
/// # Errors
/// Returns an error if the file cannot be read
/// # Example
/// ```
/// use std::path::Path;
/// use xx::hash::file_hash_sha512;
/// let hash = file_hash_sha512(Path::new("test/data/foo.txt")).unwrap();
/// ```
pub fn file_hash_sha512(path: impl AsRef<Path>) -> XXResult<String> {
    let path = path.as_ref();
    debug!("Calculating SHA512 checksum for {}", display_path(path));
    let h = file_hash::<sha2::Sha512>(path)?;
    Ok(hex(h.as_slice()))
}

pub fn file_hash<H>(path: &Path) -> XXResult<sha2::digest::Output<H>>
where
    H: Digest,
{
    let mut file = file::open(path)?;
    let mut hasher = H::new();
    let mut buf = [0; 32 * 1024];
    loop {
        let n = file
            .read(&mut buf)
            .map_err(|err| XXError::FileError(err, path.to_path_buf()))?;
        if n == 0 {
            break;
        }
        hasher.update(&buf[..n]);
    }
    Ok(hasher.finalize())
}

/// Ensure that a file has a specific SHA256 checksum
/// # Arguments
/// * `path` - A path to a file
/// * `checksum` - A SHA256 checksum
/// # Errors
/// Returns an error if the checksum does not match
/// # Example
/// ```
/// # let tmpdir = tempfile::tempdir().unwrap();
/// # let test_path = tmpdir.path().join("test.txt");
/// # std::fs::write(&test_path, "foobar").unwrap();
/// use xx::hash::ensure_checksum_sha256;
/// // SHA256 hash of "foobar"
/// ensure_checksum_sha256(&test_path, "c3ab8ff13720e8ad9047dd39466b3c8974e592c2fa383d4a3960714caef0c4f2").unwrap();
/// ```
pub fn ensure_checksum_sha256(path: &Path, checksum: &str) -> XXResult<()> {
    let actual = file_hash_sha256(path)?;
    if actual != checksum {
        bail!(
            "Checksum mismatch for file {}:\nExpected: {checksum}\nActual:   {actual}",
            display_path(path),
        );
    }
    Ok(())
}

/// Ensure that a file has a specific SHA512 checksum
/// # Arguments
/// * `path` - A path to a file
/// * `checksum` - A SHA512 checksum
/// # Errors
/// Returns an error if the checksum does not match
/// # Example
/// ```
/// # let tmpdir = tempfile::tempdir().unwrap();
/// # let test_path = tmpdir.path().join("test.txt");
/// # std::fs::write(&test_path, "foobar").unwrap();
/// use xx::hash::ensure_checksum_sha512;
/// // SHA512 hash of "foobar"
/// ensure_checksum_sha512(&test_path, "0a50261ebd1a390fed2bf326f2673c145582a6342d523204973d0219337f81616a8069b012587cf5635f6925f1b56c360230c19b273500ee013e030601bf2425").unwrap();
/// ```
pub fn ensure_checksum_sha512(path: &Path, checksum: &str) -> XXResult<()> {
    let actual = file_hash_sha512(path)?;
    if actual != checksum {
        bail!(
            "Checksum mismatch for file {}:\nExpected: {checksum}\nActual:   {actual}",
            display_path(path),
        );
    }
    Ok(())
}

pub fn parse_shasums(text: &str) -> HashMap<String, String> {
    text.lines()
        .map(|l| {
            let mut parts = l.split_whitespace();
            let hash = parts.next().unwrap();
            let name = parts.next().unwrap();
            (name.into(), hash.into())
        })
        .collect()
}

/// Calculate the SHA256 hash of bytes
///
/// # Example
/// ```
/// use xx::hash::sha256;
/// let hash = sha256(b"hello world");
/// assert_eq!(hash, "b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9");
/// ```
pub fn sha256(data: &[u8]) -> String {
    let mut hasher = sha2::Sha256::new();
    hasher.update(data);
    hex(hasher.finalize().as_slice())
}

/// Calculate the SHA512 hash of bytes
///
/// # Example
/// ```
/// use xx::hash::sha512;
/// let hash = sha512(b"hello world");
/// ```
pub fn sha512(data: &[u8]) -> String {
    let mut hasher = sha2::Sha512::new();
    hasher.update(data);
    hex(hasher.finalize().as_slice())
}

// MD5 support (feature-gated)
#[cfg(feature = "hash_md5")]
/// Calculate the MD5 hash of a file
///
/// **Note**: MD5 is cryptographically broken and should not be used for security purposes.
/// It's included for compatibility with legacy systems.
///
/// # Example
/// ```
/// use std::path::Path;
/// use xx::hash::file_hash_md5;
/// let hash = file_hash_md5(Path::new("test/data/foo.txt")).unwrap();
/// ```
pub fn file_hash_md5(path: impl AsRef<Path>) -> XXResult<String> {
    let path = path.as_ref();
    debug!("Calculating MD5 checksum for {}", display_path(path));
    let mut file = file::open(path)?;
    let mut hasher = md5::Md5::new();
    let mut buf = [0; 32 * 1024];
    loop {
        let n = file
            .read(&mut buf)
            .map_err(|err| XXError::FileError(err, path.to_path_buf()))?;
        if n == 0 {
            break;
        }
        hasher.update(&buf[..n]);
    }
    Ok(hex(hasher.finalize().as_slice()))
}

#[cfg(feature = "hash_md5")]
/// Calculate the MD5 hash of bytes
///
/// **Note**: MD5 is cryptographically broken and should not be used for security purposes.
///
/// # Example
/// ```
/// use xx::hash::md5;
/// let hash = md5(b"hello world");
/// ```
pub fn md5(data: &[u8]) -> String {
    use md5::Digest;
    let mut hasher = md5::Md5::new();
    hasher.update(data);
    hex(hasher.finalize().as_slice())
}

// SHA1 support (feature-gated)
#[cfg(feature = "hash_sha1")]
/// Calculate the SHA1 hash of a file
///
/// **Note**: SHA1 is cryptographically weak and should not be used for security purposes.
/// It's included for compatibility with systems like Git.
///
/// # Example
/// ```
/// use std::path::Path;
/// use xx::hash::file_hash_sha1;
/// let hash = file_hash_sha1(Path::new("test/data/foo.txt")).unwrap();
/// ```
pub fn file_hash_sha1(path: impl AsRef<Path>) -> XXResult<String> {
    let path = path.as_ref();
    debug!("Calculating SHA1 checksum for {}", display_path(path));
    let mut file = file::open(path)?;
    let mut hasher = sha1::Sha1::new();
    let mut buf = [0; 32 * 1024];
    loop {
        let n = file
            .read(&mut buf)
            .map_err(|err| XXError::FileError(err, path.to_path_buf()))?;
        if n == 0 {
            break;
        }
        hasher.update(&buf[..n]);
    }
    Ok(hex(hasher.finalize().as_slice()))
}

#[cfg(feature = "hash_sha1")]
/// Calculate the SHA1 hash of bytes
///
/// **Note**: SHA1 is cryptographically weak and should not be used for security purposes.
///
/// # Example
/// ```
/// use xx::hash::sha1;
/// let hash = sha1(b"hello world");
/// ```
pub fn sha1(data: &[u8]) -> String {
    use sha1::Digest;
    let mut hasher = sha1::Sha1::new();
    hasher.update(data);
    hex(hasher.finalize().as_slice())
}

// Blake3 support (feature-gated)
#[cfg(feature = "hash_blake3")]
/// Calculate the Blake3 hash of a file
///
/// Blake3 is a modern, fast cryptographic hash function.
///
/// # Example
/// ```
/// use std::path::Path;
/// use xx::hash::file_hash_blake3;
/// let hash = file_hash_blake3(Path::new("test/data/foo.txt")).unwrap();
/// ```
pub fn file_hash_blake3(path: impl AsRef<Path>) -> XXResult<String> {
    let path = path.as_ref();
    debug!("Calculating Blake3 checksum for {}", display_path(path));
    let mut file = file::open(path)?;
    let mut hasher = blake3::Hasher::new();
    let mut buf = [0; 32 * 1024];
    loop {
        let n = file
            .read(&mut buf)
            .map_err(|err| XXError::FileError(err, path.to_path_buf()))?;
        if n == 0 {
            break;
        }
        hasher.update(&buf[..n]);
    }
    Ok(hasher.finalize().to_hex().to_string())
}

#[cfg(feature = "hash_blake3")]
/// Calculate the Blake3 hash of bytes
///
/// Blake3 is a modern, fast cryptographic hash function.
///
/// # Example
/// ```
/// use xx::hash::blake3;
/// let hash = blake3(b"hello world");
/// ```
pub fn blake3(data: &[u8]) -> String {
    blake3::hash(data).to_hex().to_string()
}

#[cfg(feature = "hash_blake3")]
/// Ensure that a file has a specific Blake3 checksum
pub fn ensure_checksum_blake3(path: &Path, checksum: &str) -> XXResult<()> {
    let actual = file_hash_blake3(path)?;
    if actual != checksum {
        bail!(
            "Checksum mismatch for file {}:\nExpected: {checksum}\nActual:   {actual}",
            display_path(path),
        );
    }
    Ok(())
}

#[cfg(test)]
mod tests {
    use std::io::Write;

    use super::*;

    #[test]
    fn test_hash_to_str() {
        assert_eq!(hash_to_str(&"foo"), "3e8b8c44c3ca73b7");
    }

    #[test]
    fn test_hash_sha256() {
        let tmp = tempfile::NamedTempFile::new().unwrap();
        tmp.as_file().write_all(b"Hello, world!").unwrap();
        let hash = file_hash_sha256(tmp.path()).unwrap();
        insta::assert_snapshot!(hash, @"315f5bdb76d078c43b8ac0064e4a0164612b1fce77c869345bfc94c75894edd3");
    }

    #[test]
    fn test_sha256_bytes() {
        let hash = sha256(b"hello world");
        assert_eq!(
            hash,
            "b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9"
        );
    }

    #[test]
    fn test_sha512_bytes() {
        let hash = sha512(b"hello world");
        assert!(hash.len() == 128); // SHA512 produces 128 hex characters
    }

    #[cfg(feature = "hash_md5")]
    #[test]
    fn test_md5_bytes() {
        let hash = md5(b"hello world");
        assert_eq!(hash, "5eb63bbbe01eeed093cb22bb8f5acdc3");
    }

    #[cfg(feature = "hash_sha1")]
    #[test]
    fn test_sha1_bytes() {
        let hash = sha1(b"hello world");
        assert_eq!(hash, "2aae6c35c94fcfb415dbe95f408b9ce91ee846ed");
    }

    #[cfg(feature = "hash_blake3")]
    #[test]
    fn test_blake3_bytes() {
        let hash = blake3(b"hello world");
        assert_eq!(
            hash,
            "d74981efa70a0c880b8d8c1985d075dbcbf679b99a5f9914e5aaf96b831a9e24"
        );
    }
}